Dynamic Configuration Refactoring

middlewares/stripprefix/strip_prefix.go

@@ -0,0 +1,67 @@
+package stripprefix
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"github.com/containous/traefik/config"
+	"github.com/containous/traefik/middlewares"
+	"github.com/containous/traefik/tracing"
+	"github.com/opentracing/opentracing-go/ext"
+)
+
+const (
+	// ForwardedPrefixHeader is the default header to set prefix.
+	ForwardedPrefixHeader = "X-Forwarded-Prefix"
+	typeName              = "StripPrefix"
+)
+
+// stripPrefix is a middleware used to strip prefix from an URL request.
+type stripPrefix struct {
+	next     http.Handler
+	prefixes []string
+	name     string
+}
+
+// New creates a new strip prefix middleware.
+func New(ctx context.Context, next http.Handler, config config.StripPrefix, name string) (http.Handler, error) {
+	middlewares.GetLogger(ctx, name, typeName).Debug("Creating middleware")
+	return &stripPrefix{
+		prefixes: config.Prefixes,
+		next:     next,
+		name:     name,
+	}, nil
+}
+
+func (s *stripPrefix) GetTracingInformation() (string, ext.SpanKindEnum) {
+	return s.name, tracing.SpanKindNoneEnum
+}
+
+func (s *stripPrefix) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	for _, prefix := range s.prefixes {
+		if strings.HasPrefix(req.URL.Path, prefix) {
+			req.URL.Path = getPrefixStripped(req.URL.Path, prefix)
+			if req.URL.RawPath != "" {
+				req.URL.RawPath = getPrefixStripped(req.URL.RawPath, prefix)
+			}
+			s.serveRequest(rw, req, strings.TrimSpace(prefix))
+			return
+		}
+	}
+	http.NotFound(rw, req)
+}
+
+func (s *stripPrefix) serveRequest(rw http.ResponseWriter, req *http.Request, prefix string) {
+	req.Header.Add(ForwardedPrefixHeader, prefix)
+	req.RequestURI = req.URL.RequestURI()
+	s.next.ServeHTTP(rw, req)
+}
+
+func getPrefixStripped(s, prefix string) string {
+	return ensureLeadingSlash(strings.TrimPrefix(s, prefix))
+}
+
+func ensureLeadingSlash(str string) string {
+	return "/" + strings.TrimPrefix(str, "/")
+}

middlewares/stripprefix/strip_prefix_test.go

@@ -0,0 +1,169 @@
+package stripprefix
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/containous/traefik/config"
+	"github.com/containous/traefik/testhelpers"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestStripPrefix(t *testing.T) {
+	testCases := []struct {
+		desc               string
+		config             config.StripPrefix
+		path               string
+		expectedStatusCode int
+		expectedPath       string
+		expectedRawPath    string
+		expectedHeader     string
+	}{
+		{
+			desc: "no prefixes configured",
+			config: config.StripPrefix{
+				Prefixes: []string{},
+			},
+			path:               "/noprefixes",
+			expectedStatusCode: http.StatusNotFound,
+		},
+		{
+			desc: "wildcard (.*) requests",
+			config: config.StripPrefix{
+				Prefixes: []string{"/"},
+			},
+			path:               "/",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/",
+			expectedHeader:     "/",
+		},
+		{
+			desc: "prefix and path matching",
+			config: config.StripPrefix{
+				Prefixes: []string{"/stat"},
+			},
+			path:               "/stat",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/",
+			expectedHeader:     "/stat",
+		},
+		{
+			desc: "path prefix on exactly matching path",
+			config: config.StripPrefix{
+				Prefixes: []string{"/stat/"},
+			},
+			path:               "/stat/",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/",
+			expectedHeader:     "/stat/",
+		},
+		{
+			desc: "path prefix on matching longer path",
+			config: config.StripPrefix{
+				Prefixes: []string{"/stat/"},
+			},
+			path:               "/stat/us",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/us",
+			expectedHeader:     "/stat/",
+		},
+		{
+			desc: "path prefix on mismatching path",
+			config: config.StripPrefix{
+				Prefixes: []string{"/stat/"},
+			},
+			path:               "/status",
+			expectedStatusCode: http.StatusNotFound,
+		},
+		{
+			desc: "general prefix on matching path",
+			config: config.StripPrefix{
+				Prefixes: []string{"/stat"},
+			},
+			path:               "/stat/",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/",
+			expectedHeader:     "/stat",
+		},
+		{
+			desc: "earlier prefix matching",
+			config: config.StripPrefix{
+
+				Prefixes: []string{"/stat", "/stat/us"},
+			},
+			path:               "/stat/us",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/us",
+			expectedHeader:     "/stat",
+		},
+		{
+			desc: "later prefix matching",
+			config: config.StripPrefix{
+				Prefixes: []string{"/mismatch", "/stat"},
+			},
+			path:               "/stat",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/",
+			expectedHeader:     "/stat",
+		},
+		{
+			desc: "prefix matching within slash boundaries",
+			config: config.StripPrefix{
+				Prefixes: []string{"/stat"},
+			},
+			path:               "/status",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/us",
+			expectedHeader:     "/stat",
+		},
+		{
+			desc: "raw path is also stripped",
+			config: config.StripPrefix{
+				Prefixes: []string{"/stat"},
+			},
+			path:               "/stat/a%2Fb",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/a/b",
+			expectedRawPath:    "/a%2Fb",
+			expectedHeader:     "/stat",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			var actualPath, actualRawPath, actualHeader, requestURI string
+			next := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				actualPath = r.URL.Path
+				actualRawPath = r.URL.RawPath
+				actualHeader = r.Header.Get(ForwardedPrefixHeader)
+				requestURI = r.RequestURI
+			})
+
+			handler, err := New(context.Background(), next, test.config, "foo-strip-prefix")
+			require.NoError(t, err)
+
+			req := testhelpers.MustNewRequest(http.MethodGet, "http://localhost"+test.path, nil)
+			resp := &httptest.ResponseRecorder{Code: http.StatusOK}
+
+			handler.ServeHTTP(resp, req)
+
+			assert.Equal(t, test.expectedStatusCode, resp.Code, "Unexpected status code.")
+			assert.Equal(t, test.expectedPath, actualPath, "Unexpected path.")
+			assert.Equal(t, test.expectedRawPath, actualRawPath, "Unexpected raw path.")
+			assert.Equal(t, test.expectedHeader, actualHeader, "Unexpected '%s' header.", ForwardedPrefixHeader)
+
+			expectedURI := test.expectedPath
+			if test.expectedRawPath != "" {
+				// go HTTP uses the raw path when existent in the RequestURI
+				expectedURI = test.expectedRawPath
+			}
+			assert.Equal(t, expectedURI, requestURI, "Unexpected request URI.")
+		})
+	}
+}